Why do Mercury optical encoders use a laser in the sensor readhead?

Celera Motion’s Mercury encoders rely on light intereference and talbot imaging to detect fringe changes as the scale moves relative to the readhead. Because light from lasers is coherent, the diffracted light intereferes to create an image of the scale, which is called the talbot image. Benefits of using a laser versus an LED are lower power consumption and lower thermal rise.

Click for more information on the Mercury optical encoders.
For more information on talbot imaging in optical encoders, click here.